Corrosion of metal structures is a well-understood phenomenon, and occurs when the metal gives up electrons by electrochemical reactions with its surrounding environment. Such corrosion may be prevented by forcing electrons into the metal from an external power source at a rate which is at least just as great as the rate of electrons leaving the metal to participate in the corrosion-causing electrochemical reaction occurring between the metal and its environment.
One commonly used approach to achieve this is impressed current cathodic protection, whereby an electromotive force (EMF) is used to provide electrons directly to the metal structure in its operating environment. This prevents the metal structure from serving as a source of the electrons that would otherwise be required for the corrosion reaction to proceed.
Several approaches for providing impressed current cathodic protection to metal structures fabricated of stainless steel have been described. For example, U.S. Pat. No. 4,152,236 to Beese et al. is directed to acathodic current from a DC current source applied through a platinum electrode, which provides protection to stainless steel from pitting corrosion particularly in the interior of long narrow stainless steel tubes exposed to hot concentrated chloride brine.
U.S. Pat. No. 4,285,787 to Garner et al. is directed to a method for electrochemical corrosion protection of a partly submersed, rotating, stainless steel drum in a vat containing a corrosive, oxidizing, chloride-containing bleach liquor.
In general, corrosion protection is required in industrial applications. There is,therefore,a need to provide an apparatus and method for providing electrochemical corrosion protection in such applications.